Isophorone diisocyanate was first reacted with bis(3-(1-methoxy-2-hydroxypropoxy) propyl) terminated polysiloxanes (PMTS) to attach cyanate groups to polysiloxane chain terminals

followed by reaction of these cyanate-containing polysiloxanes with poly(propylene glycol) to get polysiloxanes modified polyurethane prepolymers (PSU).Hydroxyethyl acrylate (HEA) was then used as coupling agent to react with the PSU to introduce vinyl groups in order to conduct graft-polymerization with acrylics in the subsequent step to finally get polysiloxane-polyacrylic modified polyurethane (PSU-H-AC) ternary grafting hybrid latexes.Non-grafting polysiloxane-polyacrylic-polyurethane (PSU-AC) ternary hybrid latexes were also prepared under the same experimental conditions without HEA used.Results revealed that

regardless of use of HEA

the particle size of the ternary latexes was decreased when PMTS was used.This decrease was more pronounced with a narrower size distribution in PAC grafted ternary latexes than that observed in the latexes without HEA

i.e.PSU-AC series.Higher surface tension in the PAC grafted ternary latexes was also detected as compared with the corresponding ternary latexes without grafting between PU and PAC.Examination of the latex film morphology on the intersection by SEM showed that homogeneous latex films without any phase separation were obtained from the ternary latexes when HEA was used

while aggregates and defaults were observed in the ternary films without HEA.Both measurements of water absorption of the films and of contact angle of water on surface of the films indicated that water resistance was significantly enhanced by PAC grafting on PU through incorporation of HEA during the preparation of the ternary latexes.Employment of PMTS of different molecular weight in the latex preparation and property characterization demonstrated that

to achieve an optimum for the performance of the ternary latex films

molecular weight of PMTS should be limited to 2000 and its content should be not less than 5 wt% in PMTS-PU prepolymers.